1. Field of the Invention
The present invention relates to a deflection yoke (DY) of Braun tube, and more particularly, to a deflection yoke of Braun tube having an auxiliary coil which is capable of preventing a back electromotive force according to a main magnetic field even though the auxiliary coil is disposed at a portion where a main coil of a deflection yoke is disposed, to thereby complement characteristics of the main coil, and a method for fabricating an auxiliary coil of the deflection yoke.
2. Description of the Background Art
FIG. 1 shows a side view of a general Braun tube in accordance with a conventional art.
As shown in the drawing, Braun tube 1 includes a screen 3 on which an electron beam 10 radiated from an electron gun 2 is reproduced as a picture, and a deflection yoke 20 for deflecting the electron beam 10 coming from the electron gun 2 onto a corresponding fluorescent surface of the screen 3.
FIG. 2A is a side view of a saddle-saddle type deflection yoke and FIG. 2B is a plan view of the saddle-saddle type deflection yoke viewed from its opening side.
As shown in FIG. 2A, the saddle-saddle type deflection yoke 20 for Braun tube includes a horizontal deflection coil 21 for horizontal deflection, a vertical deflection coil 22 for vertical deflection, a ferrite core 23 for complementing a magnetic force generated by the current flowing to the horizontal deflection coil 21 and the vertical deflection coil 22 and improving a deflection efficiency; a holder 24 for mechanically determining relative positions of the horizontal deflection coil 21, the vertical deflection coil 22 and the ferrite core 23 and mechanically fixing and combining them; a convergence yoke (or, called comma-free coil) typically disposed at a neck portion 29 of the holder 24 for improving a comma aberration generated by a vertical barrel type magnetic field; a ring band 26 disposed at the end of the neck portion of the holder 24 for mechanically combining the Braun tube 1 and the deflection yoke 20; and a magnet 27 typically disposed at the end of an opening 28 of the deflection yoke 20 for correcting a raster distortion appearing at the upper end portion and a lower end portion of the screen.
Thusly constructed deflection yoke 20 of the Braun tube generates a deflection magnetic field as current having a predetermined wave form is applied to the horizontal deflection coil 21 and the vertical deflection coil 22. In this respect, generally, the distribution of each deflection coil is adjusted in the lengthy direction, so that the red, green and blue electron beams 10 starting from different points can be converged to the same point on the screen and the outermost angle raster form (refer to reference numeral 61 of FIG. 8) can make a straight line with a predetermined size.
A signal in synchronization with the horizontal and vertical deflection current may flow to the convergence yoke 25, so as to complement characteristics that is not enough to complete convergence by merely adjusting the distribution in the lengthy direction of the horizontal deflection coil 21 and the vertical deflection coil 22.
Failure of converging the red, green and blue electron beams 10 to one point on the screen is called misconvergence (refer to reference numeral 62 of FIG. 8). Conventionally, the misconvergence has been complemented in a manner that a convergence yoke 25 is usually installed at the neck portion 29 of the deflection yoke, the starting point of the electron beams 10 to thereby complement the initial position.
However, such method is limitedly adopted due to the following technical limitations.
First, in case of using the horizontal deflection current, the inductance is not possibly generated by above a predetermined level only with the use of the convergence yoke 25, so that it is not applicable to a high frequency-adopted Braun tube. Thus, due to the limitation factor that the inductance is to be generated by below a predetermined level, its application is not easy in general cases where an additional circuit is not employed.
Secondly, in case of using the convergence yoke 25, the length of a magnetic pole in use for the convergence yoke 25 is to be adjusted to the length limited in a neck portion. Thus, in order to have an effect at a favorable level, the number of turns of a coil should be increased to set an inductance value very high. However, due to the limitation to the space, winding of coil is limited, and thus, it is very difficult to lower a resistance. Accordingly, in case of using the vertical deflection current, there is a limitation for application.
Thirdly, as shown in FIGS. 5A and 5B, a ferrite core winding auxiliary coil 65 is installed at the position of the main deflection coil, not at the position of the convergence yoke 25. In this case, however, the auxiliary coil 65 interacts with the magnetic field mostly formed by the horizontal deflection coil 21, so that if a protective circuit is not provided therefor, the horizontal deflection magnetic field is much damaged, causing a difficulty in implementing a desired characteristic. In addition its application incurs much expense.
Therefore, an object of the present invention is to provide a deflection yoke of Braun tube having an auxiliary coil which are capable of complementing misconvergence of a deflection yoke of Braun tube without using an additional circuit and capable of reducing power consumption.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a deflection yoke of Braun tube having a horizontal deflection coil for horizontally deflecting electron beams radiated from an electron gun, a vertical deflection coil for vertically deflecting the electron beams, and a holder inserted between the horizontal and the vertical deflection coils for mechanically fixing them and electrically insulating them, including: an auxiliary coil having a first deflection portion coil extendedly formed from a xe2x80x983-o""clockxe2x80x99 position at a neck side to a xe2x80x983-o""clockxe2x80x99 direction of a screen side on the basis of the lengthy direction of the deflection coil; a first flange coil extendedly formed for a predetermined length from a xe2x80x983-o""clockxe2x80x99 position at the screen side to a xe2x80x9812-o""clockxe2x80x99 direction of the screen side; a second deflection portion coil extendedly formed for a predetermined length from a xe2x80x9812-o""clockxe2x80x99 position at the screen side to a xe2x80x9812-o""clockxe2x80x99 direction of the neck side; a second flange coil extendedly formed for a predetermined length from a xe2x80x9812-o""clockxe2x80x99 position at the neck side to a xe2x80x989-o""clockxe2x80x99 direction of the neck side; a third deflection portion coil extendedly formed for a predetermined length from a xe2x80x989-o""clockxe2x80x99 position at the neck side to a xe2x80x989-o""clockxe2x80x99 direction of the screen side; a third flange coil extendedly formed from a xe2x80x989-o""clockxe2x80x99 position at the screen side to a xe2x80x986-o""clockxe2x80x99 direction of the screen side; a fourth deflection portion coil extendedly formed for a predetermined length from a xe2x80x986-o""clockxe2x80x99 position at the screen side to a xe2x80x986-o""clockxe2x80x99 direction of the neck side; and a fourth flange coil extendedly formed from a xe2x80x986-o""clockxe2x80x99 position at the neck side to a xe2x80x983-o""clockxe2x80x99 direction of the neck side.
The auxiliary coil of the deflection yoke of Braun tube of the present invention is preferably installed at the holder of the deflection yoke.
The auxiliary coil of the deflection yoke of Braun tube of the present invention is preferably installed at a neck side of the deflection yoke.
To the auxiliary coil of the deflection yoke of Braun tube of the present invention, current in synchronization with a vertical deflection current is preferably applied.
To the auxiliary coil of the deflection yoke of Braun tube of the present invention, current in synchronization with a horizontal deflection current is preferably applied.
To the auxiliary coil of the deflection yoke of Braun tube of the present invention, current in synchronization with a horizontal deflection current and a vertical deflection current is preferably applied.
The auxiliary coil of the deflection yoke of Braun tube of the present invention is preferably installed at a neck portion of Braun tube.
In order to achieve the above objects, there is also provided a method for fabricating an auxiliary coil of a deflection yoke of Braun tube having a horizontal deflection coil for horizontally deflecting electron beams radiated from an electron gun, a vertical deflection coil for vertically deflecting the electron beams, a holder inserted between the horizontal and the vertical deflection coils for mechanically fixing them and electrically insulating them, and an auxiliary coil installed between the horizontal and the vertical deflection coils to complement misconvergence, including the steps of: fabricating an auxiliary coil having a first deflection portion coil extendedly formed from a xe2x80x983-o""clockxe2x80x99 position at a neck side to a xe2x80x983-o""clockxe2x80x99 direction of a screen side on the basis of the lengthy direction of the deflection coil; fabricating a first flange coil extendedly formed for a predetermined length from a xe2x80x983-o""clockxe2x80x99 position at the screen side to a xe2x80x9812-o""clockxe2x80x99 direction of the screen side; fabricating a second deflection portion coil extendedly formed for a predetermined length from a xe2x80x9812-o""clockxe2x80x99 position at the screen side to a xe2x80x9812-o""clockxe2x80x99 direction of the neck side; fabricating a second flange coil extendedly formed for a predetermined length from a xe2x80x9812-o""clockxe2x80x99 position at the neck side to a xe2x80x989-o""clockxe2x80x99 direction of the neck side; fabricating a third deflection portion coil extendedly formed for a predetermined length from a xe2x80x989-o""clockxe2x80x99 position at the neck side to a xe2x80x989-o""clockxe2x80x99 direction of the screen side; fabricating a third flange coil extendedly formed from a xe2x80x989-o""clockxe2x80x99 position at the screen side to a xe2x80x986-o""clockxe2x80x99 direction of the screen side; fabricating a fourth deflection portion coil extendedly formed for a predetermined length from a xe2x80x986-o""clockxe2x80x99 position at the screen side to a xe2x80x986-o""clockxe2x80x99 direction of the neck side; and fabricating a fourth flange coil extendedly formed from a xe2x80x986-o""clockxe2x80x99 position at the neck side to a xe2x80x983-o""clockxe2x80x99 direction of the neck side.
In the method for fabricating an auxiliary coil of a deflection yoke in accordance with the present invention, it is preferred that the auxiliary coil is formed having the same length as that of the vertical deflection coil according to a pattern of misconvergence.
In the method for fabricating an auxiliary coil of a deflection yoke in accordance with the present invention, it is preferred that the auxiliary coil is formed having the same length as that of the horizontal deflection coil according to a pattern of misconvergence.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.